A bicycle sprocket has a rotational center axis. The bicycle sprocket comprises a sprocket body and sprocket teeth. The sprocket teeth include at least one first tooth and at least one second tooth. The at least one first has a first radial-tooth height. The at least one second tooth is adjacent to the first tooth and disposed on a downstream side in a rotational driving direction of the bicycle sprocket. The at least one second tooth has a second radial-tooth height. The first radial-tooth height is greater than the second radial-tooth height. The at least one first tooth includes a tooth tip having an axial center plane in an axial direction. The axial center plane of the tooth tip is offset from the axial center plane of the sprocket body in the axial direction.
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1. A bicycle sprocket having a rotational center axis, the bicycle sprocket comprising:
a sprocket body having an axial center plane perpendicular to the rotational center axis, the axial center plane of the sprocket body being provided at an axial center of the sprocket body in an axial direction parallel to the rotational center axis;
sprocket teeth including
at least one first tooth configured to engage with outer link plates of a bicycle chain and having a first radial-tooth height, the at least one first tooth having a first chain-engaging axial width which is smaller than a first distance defined between opposed outer link plates of the bicycle chain and which is larger than a second distance defined between opposed inner link plates of the bicycle chain, and
at least one second tooth adjacent to the first tooth and disposed on a downstream side in a rotational driving direction of the bicycle sprocket, the at least one second tooth being configured to engage with inner link plates of the bicycle chain, the at least one second tooth having a second radial-tooth height, the first radial-tooth height being greater than the second radial-tooth height,
the at least one first tooth including a tooth tip having an axial center plane perpendicular to the rotational center axis, the axial center plane of the tooth tip being provided at an axial center of the tooth tip in the axial direction,
the tooth tip having a rectangular shape longitudinally extending in a circumferential direction of the bicycle sprocket, and
the axial center plane of the tooth tip being offset from the axial center plane of the sprocket body in the axial direction.
2. The bicycle sprocket according to
the sprocket teeth include
a plurality of first teeth as the at least one first tooth, and
a plurality of second teeth as the at least one second tooth.
3. The bicycle sprocket according to
the at least one first tooth and the at least one second tooth are alternatively arranged in the circumferential direction of the bicycle sprocket.
5. The bicycle sprocket according to
the at least one first tooth and the at least one second tooth are alternatively arranged on a whole circumference of the sprocket body in the circumferential direction.
6. The bicycle sprocket according to
the at least one second tooth has a second chain-engaging axial width which is smaller than the second distance.
7. The bicycle sprocket according to
the sprocket teeth are integrally provided with the sprocket body as a single unitary member.
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The present application is a continuation application of the U.S. patent application Ser. No. 14/283,165 filed May 20, 2014. The contents of this application are incorporated herein by reference in their entirety.
The present invention relates to a bicycle sprocket.
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component that has been recently redesigned is a bicycle sprocket.
Most bicycles have a drive train that uses the bicycle sprocket to transmit the pedaling action from the rider to a bicycle wheel through a bicycle chain. A front sprocket and a rear sprocket have been known as the bicycle sprocket. The bicycle sprocket generally includes a plurality of teeth to engage with the bicycle chain.
In accordance with an aspect of the present invention, a bicycle sprocket has a rotational center axis. The bicycle sprocket comprises a sprocket body and sprocket teeth. The sprocket body has an axial center plane in an axial direction parallel to the rotational center axis. The sprocket teeth include at least one first tooth and at least one second tooth. The at least one first tooth is configured to engage with outer link plates of a bicycle chain and has a first radial-tooth height. The at least one first tooth has a first chain-engaging axial width which is smaller than a first distance defined between opposed outer link plates of the bicycle chain and which is larger than a second distance defined between opposed inner link plates of the bicycle chain. The at least one second tooth is adjacent to the first tooth and disposed on a downstream side in a rotational driving direction of the bicycle sprocket. The at least one second tooth is configured to engage with inner link plates of the bicycle chain. The at least one second tooth has a second radial-tooth height. The first radial-tooth height is greater than the second radial-tooth height. The at least one first tooth includes a tooth tip having an axial center plane in the axial direction. The axial center plane of the tooth tip is offset from the axial center plane of the sprocket body in the axial direction.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
The embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.
Referring initially to
The bicycle sprocket 10 is configured to be fastened to crank connecting arms 2a of a sprocket mounting member 2 by bolts (not shown). The sprocket mounting member 2 is fastened on a crank arm 4 to be rotatable integrally with the crank arm 4 about the rotational center axis A. The sprocket mounting member 2 can also be integrally provided with the crank arm 4 as a single unitary member. Namely, the bicycle sprocket 10 is configured to be rotatable integrally with the sprocket mounting member 2 and the crank arm 4 about the rotational center axis A. The bicycle sprocket 10 is configured to be rotated about the rotational center axis A in a rotational driving direction D11 during the pedaling. The rotational driving direction D11 is defined along a circumferential direction D1 of the bicycle sprocket 10. A direction D12 is defined along the circumferential direction D1. The direction D12 is opposite to the rotational driving direction D11.
As seen in
The bicycle sprocket 10 further comprises a sprocket body 18 having an annular shape. The sprocket teeth 12 radially outwardly protrude from the sprocket body 18. The at least one first tooth 14 and the at least one second tooth 16 are alternately arranged on a whole circumference of the sprocket body 18 in the circumferential direction D1. The sprocket body 18 is configured to be fastened to the crank connecting arms 2a of the sprocket mounting member 2 by bolts (not shown). In the illustrated embodiment, the sprocket teeth 12 and the sprocket body 18 comprise a metallic material such as aluminum, iron and titanium. The sprocket teeth 12 are integrally provided with the sprocket body 18 as a single unitary member. The sprocket teeth 12 can, however, be separately provided from the sprocket body 18.
As seen in
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With the bicycle sprocket 10, as seen in
Furthermore, since contact between the second tooth 16 and the bicycle chain 1 can reduce contact pressure between the first tooth 14 and the bicycle chain 1, it is possible to reduce wear of the first tooth 14 compared with a comparative bicycle sprocket including only the first tooth 14 without the second tooth 16. Accordingly, it is possible to maintaining the service life of the bicycle sprocket 10 with improving the holding function of the bicycle sprocket 10 for the bicycle chain 1.
A bicycle sprocket 210 in accordance with a second embodiment will be described below referring to
As seen in
As seen in
With the bicycle sprocket 210, the chamfered part 222 can reduce wear of the first tooth 14 in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment.
A bicycle sprocket 310 in accordance with a third embodiment will be described below referring to
As seen in
In the illustrated embodiment, the bicycle sprocket 310 further comprises an additional tooth 317. The additional tooth 317 is disposed between adjacent two of the first teeth 14 such that the bicycle chain 1 is shifted between the bicycle sprocket 10 and an additional bicycle sprocket 350 (
As seen in
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As seen in
As described above, the bicycle sprocket 10 in accordance with the first embodiment can be applied to a bicycle sprocket assembly for shifting gears.
A bicycle sprocket 410 in accordance with a fourth embodiment will be described below referring to
As seen in
Materials of the multi-layered structure of the sprocket teeth 12 are not limited to the above embodiment. For example, the second sprocket layer 432 can be made of a second-layer material comprising aluminum. In such embodiment, the second sprocket layer 432 is bonded to the first sprocket layer 430 and the third sprocket layer 434 using diffusion bonding or bonding material such as adhesive.
With the bicycle sprocket 410, the multi-layered structure can save weight of the sprocket teeth 12 in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment.
A bicycle sprocket 510 in accordance with a fifth embodiment will be described below referring to
As seen in
With the bicycle sprocket 510, the closed openings 513 and 515 can save weight of the sprocket teeth 12 in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment.
A bicycle sprocket 610 in accordance with a sixth embodiment will be described below referring to
As seen in
Similarly, as seen in
With the bicycle sprocket 610, the cutout 617 allows the first tooth 14 to absorb a shock caused by the first tooth 14 and the bicycle chain 1, and thereby it is possible to improve wear resistance of the first tooth 14, in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment. Similarly, the cutout 619 allows the second tooth 16 to absorb a shock caused by the second tooth 16 and the bicycle chain 1, and thereby it is possible to improve wear resistance of the second tooth 16, in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment.
A bicycle sprocket 710 in accordance with a seventh embodiment will be described below referring to
As seen in
The bicycle sprocket 710 further comprises a sprocket body 718 having an annular shape. The sprocket teeth 712 are separate members from each other and are spaced apart from each other in the circumferential direction D1 of the bicycle sprocket 710. The sprocket body 718 is configured to be fastened to the crank connecting arms 2a of the sprocket mounting member 2 by bolts (not shown).
Each of the sprocket teeth 712 includes a base part and a tooth part. In the illustrated embodiment, the first tooth 714 includes a base part 714a and a tooth part 714b. The base part 714a is implanted in the sprocket body 718. The tooth part 714b radially outwardly protrudes from the base part 714a. Similarly, the second tooth 716 includes a base part 716a and a tooth part 716b. The base part 716a is implanted in the sprocket body 718. The tooth part 716b radially outwardly protrudes from the base part 716a.
Each of the sprocket teeth 712 is made of a first material comprising a metallic material e.g. which can be selected from a group comprising aluminum, titanium or iron. The sprocket body 718 is made of a second material which is lighter than the first material. For example, such a second material can be selected from a group comprising aluminum, titanium and a resin material. The first teeth 714 and the second teeth 716 are at least partially embedded in the sprocket body 718 by integral molding such as insertion molding.
With the bicycle sprocket 710, since the sprocket body 718 is made of the second material comprising a resin material, it is possible to save weight of the bicycle sprocket 710 in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment.
A bicycle sprocket 810 in accordance with an eighth embodiment will be described below referring to
As seen in
In the illustrated embodiment, each of the first teeth 14 has a center line CL1 radially extending from the rotational axis A of the bicycle sprocket 810. Each of the first teeth 14 has a symmetrical shape with respect to the center line CL1. More specifically, each of the first teeth 14 has a symmetrical shape with respect to the center line CL1 when viewed from a direction of the rotational axis A.
As seen in
Similarly, as seen in
As seen in
With the bicycle sprocket 810, since each of the sprocket teeth 12 has a symmetrical shape with respect to the center line CL1 or CL2, both circumferential sides of the sprocket tooth 12 can be used as a driving side configured to face in the rotational driving direction D11. This allows the bicycle sprocket 810 to be used as a both-side usable sprocket in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment.
A bicycle sprocket 910 in accordance with a ninth embodiment will be described below referring to
As seen in
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With the bicycle sprocket 910, the first radial contact part 960 is configured to contact the intermediate portions 1g of the outer link plates 1d of the bicycle chain 1 in the radial direction D4. Accordingly, the first radial contact part 960 can improve stability of the outer link plates 1d engaging with the first tooth 14 in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment.
Similarly, the second radial contact part 964 is configured to contact the intermediate portions 1h of the inner link plates 1c of the bicycle chain 1 in the radial direction D4. Accordingly, the second radial contact part 964 can improve stability of the inner link plates 1c engaging with the second tooth 16 in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment.
A bicycle sprocket 1010 in accordance with a tenth embodiment will be described below referring to
As seen in
With the bicycle sprocket 1010, it is possible to save weight of the bicycle sprocket 1010 in addition to the advantageous effect obtained by the bicycle sprocket 10 in accordance with the first embodiment.
A bicycle sprocket 1110 in accordance with an eleventh embodiment will be described below referring to
As seen in
The at least one second tooth 1116 is adjacent to the first tooth 14 and disposed on a downstream side in the rotational driving direction D11 of the bicycle sprocket 1110. In the illustrated embodiment, the second tooth 1116A is adjacent to the first tooth 14A and disposed on a downstream side with respect to the first tooth 14A in the rotational driving direction D11 of the bicycle sprocket 1110.
The at least one second tooth 1116 is configured to engage with the inner link plates 1c of the bicycle chain 1. The at least one second tooth 1116 has a second radial-tooth height H112. The first radial-tooth height H1 is greater than the second radial-tooth height H112. In the illustrated embodiment, the second radial-tooth height H112 of the second teeth 1116 is less than the second radial-tooth height H2 of the second teeth 16 in accordance with the first embodiment.
As seen in
With the bicycle sprocket 1110, it is possible to obtain the same advantageous effect as that of the bicycle sprocket 10 in accordance with the first embodiment.
In the above embodiments, the term “attached” or “attaching”, as used herein, encompasses configurations in which an element directly attached to another element by affixing the element is directly to the other element; configurations in which the element is indirectly attached to the other element via the intermediate member(s); and configurations in which one element is integral with another element, i.e. one element is essentially part of the other element. This concept also applies to words of similar meaning, for example, “joined”, “connected”, “coupled”, “mounted”, “fixed” and their derivatives except for the terms “bonded” and “bonding.”
The term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. This concept also is applied to words of similar meaning, for example, the terms “have”, “include” and their derivatives.
The terms “member”, “section”, “portion”, “part” or “element” when used in the singular can have the dual meaning of a single part or a plurality of parts.
The ordinal numbers such as the terms “first” or “second” recited in the present application are merely identifiers, but do not have any other meanings, for example, a particular order and the like. Moreover, for example, the term “first element” itself does not imply an existence of “second element”, and the term “second element” itself does not imply an existence of “first element.”
Finally, terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
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